In Figure, Rs is to be adjusted in value by moving the sliding contact across it until

Question:

In Figure, Rs is to be adjusted in value by moving the sliding contact across it until points a and b are brought to the same potential. (One test for this condition by momentarily connecting a sensitive ammeter between a and b if these points are at the same potential. the ammeter will not deflect.) Show that when this adjustment is made, the following relation holds: Rx = Rs R2/Rr. An unknown resistance (Rx) can be measured in terms of a standard (Rs) using this device, which is called a Wheatstonebridge.